Hydraulic well drilling device



June 10, 1947. E. MERTEN 2,452,031

HYDRAULIC WELL DRILLING DEVICE Filed June 19,- 1944 3 Sheets-Sheet 2Invznfor: Euqzn- Mel-fen June 10, 1947.

E MERTEN HYDRAULIC WELL DRILLING DEVICE 3 Sheets-Sheet 3 Filed June 19,1944 Fig. u

lnvemor: Eugen Mel-fen Patented June 10, 1947 TED STATES PATENT o Fri-csHYDRAULIC WELL DRILLING DEVICE iEugen Morten, Houston, Tex, assi gnor:to shell Development (Jumpany, San Francisco, ,Calif., .a corporationof Delaware Application June 19, 1944,'Serial No.'540,9'89

.The present invention pertains'to the drilling of Wells, exploratorylboreholesrand therli'ke, and "relates more particularly ito an improvedhydraulic drilling device.

.Botlrrotary tools ian'drcablet-tools of the percus- It is thereformanobject cof this invention to i provide :a drilling device especiallyadapted 'for "drillinggat anydesirable depth, through extremely:hardformations; the: impact actionzofitheconsiderable'mass vofthepresent'drilling device being efiectivein'cracking thin formationsorvlayers of .r'ha'rdyrook. Sincethisimpact-action is notdependentonithe :degree of sharpness of the drill bitgthe'necessityvofreplacing-worn out bits is i re- .duceditoaaiminimmn sandra,rapid rateofipenetra- 'tioirinto eitherthin or tthickrhard formationsis 1achieved.

it is also an :object.zofithisxinvention'to :provide a hydraulicdrilling system wherein the reciproeating action of a: percussion"typesbit iszoontroll'ed b avaive responsive.to idiffierentialipressuresgeneratecli'hy the fiowrof a; *hydrauliciorpressure *fluid through thebit.

It is .also *an obj ect Oflthisxl'IlVEIltiOIl "tdprovide "arhydrauiic"drilling device of'tthe percussion type capaib-le of :.operating with:a variable downward stroke, :which :is =.indenemient .of the rphysicaldimensionsaoithe ireciprocatingmembers involved, :wherehy:the'rnecess'ity 0f rigorously maintaining the;;dr'i11ing device satacritical distance from the Thottom of therhoiesiseliminated'rwithoutiimpairthe efficiency of =1 the rep erations.

It: i also ian-iobject tof': thiSliIlVEIltiOiItO :provide ioiidriliiirgsystemra'vh-ich combines-the grinding "acation ofi-the rotary :tooi'wit'lrithe reciprocating :or impactingractioirof thecoahle toolgand thusposzsesses'xthe advantages of-1both driilin'g methods.

Ibis-also; ans-object of this i invention *to provide 'a' drillingsystem"whereins arotary land are'ciprocatingiinotion .isiirnnarted itothe 'bit .by rhydraulic lmeans bysupplying to the hit an actuatins treamof--:a pressure liquid thronghsa drill string rsuch -as used --inrotarysystems.

It is also an object of this ii ivQlllliQ litfilpl'fl i lfi '9 Claims.(Cl. 2554.4)

suitable -:f or use "with the 2 a drilling system z-adapted to drillboreholes hav- :ing a :diameter:largerthanthat of the-rdrill bit usedinadrilling.

It is also an object of this;invention-toprovide aidrillingsystemwherein a nangerouslyworn condition of '1 the drill'iibitaisindicated to the mperator byra rise in the pressure of the hydrauliciflu-id,

andth e drillingis automatically stopped-by means positioned, within thebit.

i'I 'hese andother objects-iofithis invention will be Ill'ldBlStOfiidfrom the following description, "taken with reference to the attached@drawings, "wherein Fig, L1 i is a diagrammatic view in l verticalcrosssection of a preferred embodiment-of the-present drilling device;

"Fig. 1A i519, fragmentany vie-W oba'modification of :the deviceotFig.1;

:Fig. .2 is another view of a modificationof the device of-Fig. 1;

:Fig. :3 is. a diagrammatic view inwvertioalcrossssection -of another--embodiment of the "present 1 drilling 1 device;

Fig: 4 is: a similar viewof a-modifieation. ofithe device of Fig. 3;

Fig. 5 is :a horizontalcross-section view taken along line 55"of.Fig. 3;y

Figs. 6 and '7 are, respectively, an: elevation and ahorizontal"cross-section view-of -a=idrill bit suitable :foruse' withthe system of the: present inven- :Figs. 6A and :7 A are-similar viewsof anothernhit suitable for use with the system of the p1".esentinvention;

:Figs. S-rand '9 .are similar 'views-,0f another bit system of 1 thepresent invention;

Fig. .10 is a view, partly in eross section, ofithe :presentidrillingdeviceprovided-With aclutch arrangement for rotary application;

Ties; ll-and 12 areidiagrammatic views of-a ibi-t arrangementadaptedtoprevent damage .to ,the .mechanism of the present drillingrdevicethroiigh the wear of the drill bit;

1318 -2, diagrammatic :viewin vcross-section oi awvalve arrangement.adapted tomaintain the hydraulic-fluid of .thelpresent system withinpredetermined pressure and circulation volume ranges;

Fig. i 14 is -a view, partly1in-.eross-section, of a modification of theupper part of the. mechanism shown? inFigs. 1' and .2.

Ref,erring to the drawings Fig. :1 showsindia- ,grammaticirfor-m apreferred embodiment .of .the

A presenthydranlio :drilling device, all. conventional sage IS. A spiderplate I3, having passages ISA therethrough, supports a plate or capmember I I within chamber I above the passage I6. Lateral ports 9provide for fluid communication between the inside and the outside ofthe string I.

The drill stem together with elements I5 and I9 forms a. stationarypiston member with regard to a movable cylinder member 5, having acentral bore 7 adapted to fit slidingly about said piston, said cylinderbeing suitably closed at the top and at the bottom, as shown at 2 andPacking elements may be provided between the piston and cylinder membersas shown at 3 and I7. The lower par-t of the cylinder 5 may be integralwith, or may have attached thereto, a cutting element or a drill bithaving any desired number of cutting blades 21, such for example as a,fishtail bit.

' Carried within the piston I 5 between the transverse plates I3 and I9is a movable valve member 8, having a cup-shaped hollow upper portion 4Aand, if desired, an elongated stem member I8 depending therefrom. A verysmall-diameter channel I2 is in fluid communication between the space 4within the hollow valve portion 4A and the space outside of said valve,The size and shape of the member 8 and of the channel I2 are selected sothat the outer orifice or orifices of said channel are at the level of aconstricted part of the flow passage through the piston when the cupmember 4A abuts the cap member I I, for example, as shown in Fig. 1, forpurposes to be described hereinbelow. The piston passage I6 is providedwith seat I4 for the valve member 8, which is adapted to close saidpassage when moved into its lowermost position as shown in Fig. 2.

Exhaust means, such as a passage 25, are provided for flushing into theborehole the fluid from the space within the cylinder.

A pin or finger member, such as a. spring 2I is provided within thelower portion of the cylinder 5 in register with the stem I8 of thevalve, being supported for example by means of a Web structure 23.

The operation of the present drilling device is as follows: a hydraulicfluid is forced under pressure downwards through the drill string I, thevalve 8 being at that time in its lowermost position against the seatI4. The central passage I6 being thus closed, as shown in Fig. 2, thefluid passes through the ports 9, and the pressure developed within thebore or space I above the piston forces the cylinder 5 upwards withregard to the stationary piston I5-I 9 thus raising the bit 21.

As the moving cylinder comes to the upper limit of its stroke, the pinor spring means 2I strikes the valve 8 and raises it until it comes incontact with the cap II. The passage I6 being thus open, the hydraulicfluid flows therethrough from the drill string I, and also from thespace I of the cylinder, and out into the borehole through the passage25. The cylinder 5 moves down by gravity, impacting the blades 21against the bottom of the borehole. As the downward motion of thecylinder begins, the yieldable means 2 motion of the movable member.

4 previously compressed against the valve 8, expands to its fullnon-stressed length, thereby still remaining in contact with said valveduring a short initial period of the downward stroke. This maintains thevalve 8 pressed against the cap II during said initial period, andpermits the flow of the fluid through the piston to create, by theVenturi effect, a pressure difierential between the relativelyrestricted passage I6 and the space above and below. The reducedpressure within the restricted passage is transmitted, through thechannel I2, to the space 4 within the cup-shaped valve, whereby said cupis firmly held by said pressure-differential or suction-cup efiect,against the cap member II during the downward stroke.

As the bit strikes the bottom of the borehole, and the downward motionof the cylinder 5 is stopped, the rate of the fluid flow through thepassage I6 is decreased, no more fluid flowing from the space I, Thedifferential pressure holding the valve 8 up is thus decreased; and thevalve drops down on the seat I4, closing the passage I6, whereafter theupward stroke of the cylinder is repeated.

Instead of the construction shown in Fig. l, the cup-shaped valve member8 may be formed without the depending projection I8, as shown in Fig.1A, In this case, the low pressure prevailing under fluid flowconditions in the relatively constricted passage I3B is applied by meansof a small communication passage or channel I2A to the inside of the cup8A, which is thus maintained pressed, by the relatively higher pressurein space I5A, against the cap IIA during the downward The operation ofthe device of Fig. 1A is in all other regards: identical with theoperation of that of Fig. 1.

It will therefore be seen that the valve structure of the presenthydraulic drilling device has the advantage of not requiring any springmeans for holding said valve in position, the holding effect beingprovided by pressure differential means, and. all difiiculties usuallyencountered in adjusting valve springs for properly timed operationunder conditions of varying pressures being thereby eliminated. Thegreat advantage of the present system resides however in its ability tooperate with a variable length stroke. It will be seen that with thearrangement shown, valve 8 will close and thereby reverse the directionof the stroke whenever the bit hits the bottom of the borehole andthereby arrests the downward motion of the cylinder, whether or not thecylinder has at this moment reached the lower limit of its stroke, asdetermined by its position with regard to the stationary piston. Thepresent variable stroke system thus eliminates the necessity ofcontinuously and accurately correlating the level of the piston 65, thatis, the length of the drill string, with the level of the bottom of theborehole or with the rate of penetration of the bit.

Fig. 2 shows a hydraulic bit similar to that of Fig. 1 and operating onthe same principle, but provided with an additional spring 3!, which iscompressed between the stationary piston and the bottom of the movablecylinder during the upward stroke of the latter. The spring 3| serves toaccelerate the bit additionally to the elfect of gravity during thedownward or impact stroke.

The bit of Fig. 2 is also provided with a valve 35, which serves toclose the exhaust passage 25 through the bit when depressed downwardsagainst the action of a spring 37, engaged between said valve and aspider 38 and tending to hold the valve up.

The operation oftlfiszv-alveis as follows: when the cylinder .5 is:aboutto reachlthe .end of .its

upward stroke, zthexspring 33 which corresponds to '.the:- spring :24 of:Fig. 1, lifts the upper :valve :8 *from-itsseat, openingthe passageI26. The valve -43 is pressed againstthe :cap H andactsttonompress firstthe. spring .33 and :then the springt3l, :thusclosing the lowervalvex35. AsJthe cylinder reverses :its motion, the bit is.impactedagainst the formation by the triple client of .:gravity, of thespring 3.I,.and.of the hydraulic :pressure of .the .fluid passingthrough .passage I16 .and acting against the lower inner face 40 ofthecylinder, whichis greaterthanthe upper innerlfacethere- 'oflby anareaequalto the cross-sectional:arearof :thetubular string I, said pressureacting at the sametime tohold the valve :35 closed'against the action ofspring :31. a

As the bit hits the bottom, and the downward 'motion of .the cylinder'isarrested; the flowpf *fiuidthrough'the passage -lfizto thelower portion332 of the cylinder ceases, the collapse of the differential pressuregenerated by said "flow-permits the valves to drop toits seat, closingthe passage [6, and the fluid pressure applied throughthe .ports "9 tothe upperportion l of :the cylinder startsanevwcycle byraising thecylinder. 'The :pressure .in the portion 132 of the cylinder below thepiston is at that time relieved by :lluid leakage through a small-.borechannel or-passage 39 between the inside and the outside :of thecylindenwhichpermits the springz3'lto overcome saidpressure and toraisethe'valve-.35,..thus open- :ing :the passage .15 and allowing'theflui'dLfmm space "3.2 :to flow into .the borehole during the :2

upward stroke of the cylinder.

Although, as seen from the above,Fig..2adiffers :fromlFigzl by theinclusion of twoadditional-ele- .ments, namely the-spring 3| andthevalve 35, it is obviouslthatthe device oilFig. 1 'cantalso ybe modifiedby adding thereto only one of said ele- .ments.

Figs. 3 and 4 show bits similar in operation'to those orFigs. 1 and.2,'but inwhich the cylinder is stationary, being attached'tothe drillstring,

whilethe bit is attached to a piston movable withinsaid cylinder.

The lowerportion of a drill stringfil 'forms or has affixed theretoanoutside.housingr53ywhich may be of a somewhat enlarged diameterasshown in the-drawing.

.Arranged concentrically with the ,outside'housing 53 :is an :insidehousing .or cylinders, attached thereto by a lower flange 185, or by aspider or welov structure :55, orboth, said rspiderrserving as a topclosure for the inner cylinder and the flange'fifi serving as bottomclosure for 'botl'rhous- .ingsor cylinders. The inside cylinderewhasinits lower portion passages or openings 83 in communication Withthe spacewithin the outside housing 53. Arranged for reciprocating action withinthe cylinder-80 is a piston 65, having \attached thereto a tubularinember orpiston rod 8!, whichppasses slidably through the flange 185and carries attached to its lower end a bit =89. The piston rod has abore iBZ openin-g at-the upper end tothe space-above thezpiston, and'inregister at the lower end with a passage :9! through-the bit forexhausting the drilling or hydraulic fluid from the cylinder into theborehole. "Packing means Bl and 8! are provided to prevent loss of fluidduring the reciprocating .action of the piston, as shown in the drawing.

The piston-.- 65, as seen fromFigs..3 .and 5,. has a plurality oflaterally arranged axial passages 164 esurroundingsthecentral bore 82of-thepistonrcd .andaopeninginto an annular openin 6.9. which ;f.orms avalvecseat for a valve structure adapted ;to :be closedwhen1 a valve;member 1-13 :is seated thereon. I

.flhe hollow or: QupshaDed-VaIVe-member 1.3 has a central openingslidingly fitting around the aDiStOl'l rod 48 I, its. downward -.motion:alon l the rstemlbeinglimitedby.a stoprmember l9, aflixed stothexrrod8. 1., and serving :as ea :closu-re :for :the -open-:end:.of thecup-shaped valve member when stheilatter-irs in its :lowermostposit-ion. .Aspring T5, positioned around the rod 8| within the hollowvalve 1-3,;islikewise-supported bythe Stop or plate 11.9; and itendsitoFierce the valve :1;3;aga-inst :itsqseat 68. Small-diameter channels."are provided throu h the walls-of the :piston "todzfl'l -ior fluidcommunication between the'boreof said-rod "and the inside of the hollowvalve.

Linkmembers Hare ainXedtothevalve-l? and apassqthrough theopenings 69and 64, being connectedabovethapistonto a spideror web mem- ..her-63,having orifices Ii l said spider being. thus adapted to movetogether-with the l valve -13.

A powerful spring 5-9 is :held in compression between the piston-.55and-the upper closure F55 .of'the inner cylinder. Pin or, finger meanssuch :as. a stem, tappet or spring?51,;affiXed-t01-the' top closure of:the cylinder, qextend down-wards into ;the cylinder, concentrically and:within the spring-59.

The operationrof the variable stroke system of ,3is asfollows:

The spring '15 expands and forces :the :hollow --v-alve 13 againstitsseatafifl, thus closing-themstonwfisagainstxfiuid flow. Thepressurefluid sup- ..plied. from the. surface through-the string 51 en-.ters-thelower;portion:of the inner cylinder-.80 throughthe ports :83and forces the piston- 65 upwards, compressing the springifi and helpingthe spring 15 to maintain the valve 13 closed --ag-ainst the seat .69.As the piston. 65 approaches .theupperlimit of its stroke, the :pinorspring 51 strikes the spider 76A and forces the valve 13 downwards. Thehydraulic fluid flows :now ';through passages. 6.4;pistonrod bore 82 andpassagerflvi into-the borehole, whilethepistomBBand the .bit .8.9.travel downward under the effect of gravity and of the spring, 59.

Ihespringfil expands-and acts to maintain the valve769-l-3-aopen duringthe-initial moments-of this downward stroke. ,Asythe spider 63 movesdownward .and out of-contact with spring .51, however; the tendencyofsthe valve l-3cto close .underithe actionof-spring T5 is counteractedby the :fact that, due to the Venturi effectalready :mentioned withregard .to Fig. 1, the pressure .within therelatively.constrictedcboreefl, .whichis applied to'the insidegofthehollow valve member --l5 thr.ough the ;.passages. l-l, islowerth-anthe .pressure .in the. cylinder space. 66 outside said hollow.valvermember, :WhiChiS therefore L maintained limits-lowermost positionagainstthe effectof spring 15. by thepressure differentialthus created.

:As the .biteBS hits the bottom-0f the borehole, iandwthedownward motionof thepiston SB is arrestedpthelfiow rate through the space-6B andtubing BI decreases. The decrease of-rthe pressure =difierential.permits'the spring 15 to close the vvalve -6'9l3, .andlthe cycle isrepeated.

It isobviousthatthe spring 5!);may, be omitted, in .-which case thedownward stroke of the .bit is effected onlytunder the-actionoffgravity.

The. embodiment of Fig.4. diners from that of Fig. .3 in that thecentral axial flow passage through the piston H is provided with aclosure or cover member H4, which is maintained in open position by aspring H9 positioned within the piston rod bore 82 and supported bymeans of a spider or rim member I20. The cover H4 has a small-diameterchannel or orifice I I3 therethrough.

The hollow valve I23 is similar to valve I3 of Fig. 3, but has asmall-diameter channel I21 in communication between the space within thehollow valve and the passage I24 through the piston. Passage I2!corresponds in its functions to passage I! of Fig. 3.

The space above the piston H5 comprises, besides the springs 5! and 59,identical to those of Fig. 3, also a pin or spring member I08 adapted toregister with and to close the cover I I4 at the end of the pistonsupward stroke.

The operation of the system of Fig. 4 is similar to that of Fig. 3,excepting that, upon the end of the upward stroke, the spring I08 closesthe cover H4 and the piston and bit structure is then forced down by thecombined effect of gravity, action of the spring 59, and pressure of thehydraulic fluid applied to the top of the piston. The hollow valve I23is maintained in its open position during the downward stroke by thedifferential pressure existing between the space I29 outside the hollowvalve, and the relatively narrow passage I24, the lower pressure withinsaid. passage I 24 being applied to the inside of the hollow valve bymeans of the channel I21.

When the bit hits the bottom of the borehole, and the downward stroke isthus ended, the spring I5 closes the bell valve due to the collapse ofthe pressure differential. At the same time, a leakage of the fluidthrough the small-diameter channel H3 relieves the pressure in the spaceabove the piston and permits the spring H9 to lift the closure I I4. Thehydraulic fluid admitted through the string 5| to the space below thepiston then moves the piston upwards, driving the fluid from the spaceabove the piston into the borehole through the piston rod bore 82.

Figs. 6 and '7 show a tubular bit member IOI, which may be similar tothe members 52'I of Figs. 1 and 2, or to members 8I--89 of Figs. 3 and4, and which is provided with blade elements I04, similar to elements 25and SI of said figures, respectively. In order to impart to this bit notonly the reciprocating or impact action described above, but also arotary or grinding action, the hydraulic liquid passages through the bitmay be given, if desired, an arcuate or spiral form such as shown at I03in Fig. '7, whereby the bit is rotated by the repelling force of thepressure liquid issuing therefrom. The twist of the passage I03 shouldbe in such a direction as to produce rotation giving a tightening actionon the threads connecting the bit to the drill string. It may be notedthat this method, inoperative in conventional rotary drilling, where thebit drags at all times on the bottom of the borehole, is extremelyeffective with the present system, the rotating motion being imparted tothe bit at such times as it is traveling upwards or downwards, and istherefore not in frictional engagement with the bottom of the borehole.

When it is desired to impart to the bit a rotary motion from thesurface, for example by means of a conventional rotary table, drivingthe drill string, the cylinder and piston members shown in Figs. 1-4 maybe provided with splines, keys, keyways and the like in order to preventtheir rotating with regard to each other. Since, however,

it is difiicult to keep such splines and keyways well fitted underconditions involving a rapid reciprocating action in a medium such aswater or especially drilling fluid, it has been found preferable to usefor this purpose the arrangement of Fig. 10, which is shown especiallyin its application to the embodiments of Figs. 1 and 2, although asimilar arrangement can obviously be used also for that of Figs. 3 and4, as will be apparent from the following.

A collar or sleeve member I25 is slidingly fitted over the drill stemabove the sliding cylinder 5A. A spring I28 has its upper end connectedto a pin I2l affixed to the drill string, and its lower end connected tosaid sleeve member as shown at I22, being thus held in tension andtending to pull the sleeve upwards. The sleeve I25 has formed thereininclined or slanting slots I39, adapted to receive pins or fingers I31,aflixed to the drill stem. The lower rim of the sleeve member I25 hasformed thereon an annular row of teeth I 3 I adapted for a grippingengagement with teeth I34 formed on the upper end of the reciprocatingcylinder member 5A. A plurality of spring members I33 maintain africtional engagement between the sleeve and the cylinder members, beingattached to one, for example to the sleeve I25, as shown in Fig. 10, anddragging over the surface of the other, for example the cylinder 5A, onwhich a band of serrations I35 may be provided to improve the frictionalgrip.

In operation, when the bit is on the bottom and it is desired to switchfrom percussion to rotary drilling, the drill string is lowered as fardown as possible, and is rotated in the proper direction, for exampleclockwise with the arrangement shown in Fig. 10. The pins or fingers I31rotate with the string, while the sleeve I25, due to the frictionaleffect of the springs I33, lags behind, thus causing the fingers I3'I totravel to the other end of the slots I39, lowering the sleeve I25 andpermitting the teeth I3I to engage the teeth I34, whereafter the bit maybe rotated from the surface by means of the drill string. When it isdesired to stop rotary drilling, the drill string is raised, disengagingthe teeth, and the tension spring I23 pulls the sleeve I25 further up toprotect the teeth from blows when the percussion or impact drilling isresumed.

If it is desired to make, by impact drilling, a hole having a diameterlarger than that obtainable with a bit of a particular size used, thismay be effected, for example, by welding two of the cutting elementsI42, on opposite sides of the bit at a slight angle with regard to theaxis of the bit, as shown in Fig. 7A. This causes the bit to bedeflected towards the side of the element I40 on the downward stroke,and in the opposite direction on the upward stroke, said seconddeflection being however smaller because of the smaller speed during theupward stroke.

A similar result may also be achieved by locating the center of gravityof the bit away from the axis of the bit, that is, away from the line ofaction of the driving force. As shown in Fig. 8, this may be effected bymeans of an asymmetrical arrangement of the cutting blades, for exampleby omitting one of the blades of a regular fourblade bit, and byreinforcing the blade I I3 which is positioned on that side towardswhich the bit is deflected and which does therefore most of the cuttingwork.

Since the present system is adapted for uninterrupted operationthroughout extended periods of time, it is sometimes advisable toprovide it 9. with. an arrangement adapted to indicate; to." the drillerthat the drill. isworni beyond .alsafe point and to stopthezrecipro'catingaction. automatically beforedam'age is done to thepresent valve systern located above the bit. Figs. 11' and lz'show suchan arrangement, wherein a bit I51, which may be of any of the typesdescribed hereinabove,

is provided withan axial passage I-53 and: a plurality of. radial o1:lateralpassages l52 in. communication therewith for exhausting orcirculating the hydraulic or'drilling fluid. The. bit. has

formed. therein. in register with said passage l53= a well or cavity156, in which a steel. plug: I 55 is held, for example by'brazing, spotwelding. or: soft soldering. The plug IliThas a downwardly tapering.conical shape. and a diameter selected so that when, as shown in Fig.12, the bitis worn beyond a safepoint, the direct hammering or poundingeffect of the plug I51 against the bottom of the borehole resultsindetaching saidsplug.

from the copper, lead or other matrix retaining, said plugin the wellI56, and in forcing it against the passage I53; which closes saidpassage and automatically stops the reciprocating action of the bit byinterrupting the. flow of the hydraulic fluid.

Since the liquid throughput of the present bit issubject to considerablevariations during each cycle, water hammer effects may sometimes occurin operation. To eliminate these effects, and at the same time toprovide the proper volumeof circulating liquid. for flushing theborehole, a special valve may lee-provided whereby the fluid consumptionof the bit. is regulated or heldv at a desired. value; This-valve may bemounted either in thewolkingcylinder of the present device, or in thedrilLstring at any suitable distance above the bit. Fig..13. shows anenlarged section: I-lidof the drill'string H, which is provided with aport or. ports I69: A beam spring I6! is securely clampedto the wall of'the pipe section 563,- andrtends to maintain the port [69: normallyclosed. When the pressure differential between the inside and theoutside of the pipe exceeds a maximum predetermined by the setting, or

strength of the spring I61, the valve I'H opens,

and'permitsa portion. of the liquid to by-passthe drill bit.

The workingcylinder. of the bit, or of the drill pipe; may also beprovidedwwith v additional ports Hi5, and the system maybe operated withthese ports either open, or closed. by means of remov able plugs W3,depending on the volumeof the fluidwhichit is desired to circulate inthe borehole.

During the drilling process, it may sometimes be desiredto move the bitup or down within-the borehole; for example for the length'of the kelly,without shutting off the circulation.

Inorder toenable the operatorsto do so without permitting thereciprocating action of the present system to start or to continue(which is dangerous when the bit is away from the bottom,

since the force of the blows is in such cases brought to bearontheshoulder contact between the piston and the cylinder, with ensuingdamage to theequipment the arrangement shown inFig. 14: may be used forthe bits of the type: shown in Figs. 1 and Z.

The inside walls of. the upper portion of the:

reciprocatingrcylinder B are provided with rel'a tively shallow grooveslfi hhavinga longitudinal oraxial length greater thanthat of the pistonI53. When. the drill stem MB is lifted until the piston. lEBdsstoppedbycontact with the upper closure? shoulder of thecylinder, the groovesl8l provide-.a=-by-pass forthe hydraulic fluidaroundl saidvpiston;whereby no pressure rise is permitted-.tddevelopym the-space above thepiston (5B,

-. as.describediwithiregardto Figs. 1 and 2, and the reciprocatingaction is not permitted to take place:

The same. result is obtained with regard to the r bits-of:the'type'shown in Figs. 3 and 4 simply by:- giving the; ports 8-3 a:vertical or axial length greater than' that oi the. piston. 65, wherebyfluid is admit-ted to.:the-spaceabove the piston when therpistonais lintits lowermost position.

Lolaims asimy, invention:

1'; mhydraulio deviceadapted to be lowered 0211.8. drillsstring into aborehole for impacting. a drill bit again'st the. bottom thereof, saiddevice comprisingicylindertan'd piston members, one of saiilmembers-beingattachedto said drill string.

and the other member being'attached to said drill bit: and movable.with. regardwto said string, and variable stroke: means forreciprocating the movable member, said: means comprising passage meansfor. admitting. a. pressure fluid from the drill string: tothe; cylindermember to one side 0tsaid pistongpassagemeans for exhausting the fluid:from-the cylinder on theother side of the pistbri;v apassage throughthepiston, said passage having'aurestricted. portion; a hollow cup-shapedvalve adapted'to close saidpistonepassage to fluid flow during theupward" stroke of the movable member, a cap member aflixed to the pistonmemher. in register with the. open face of the cupshaped valve, pinmeansaffixed to the cylinder.

memberradjacent: the passage means for exhausting the: fluid therefromadapted to force said valve to an'openposition in contact with said capmember atthe end of saidupward stroke, and channelcmeans. throng-h thewalls of the cupshaped' valve invcommunication between the restrictedportion. of the piston passage and the closedspace. defined 'withinthecup-shaped valve whenzsaidrvalve-is in contact withsaid cap member,whereby-said cup shaped valve is maintained inianzopen positionincontactwith said cap member'bya a Venturi suction effect created by the fluid:flow-'throughsaid restricted portion of the piston. passage during. thedownward stroke of thec'movablemember, and is released to a closedposition by a decrease of said'fluid flow and of sa=i*d:suction effectoccurring when the motion oi the movable. member-is arrested by theimpact or therdri-lhbit againstth'e bottom of the borehole.

2; A: hydraulic device adapted to be lowered on: a drill strings into aborehole for impacting a drill: bit. against the bottom thereof, saidudevice: comprising; cylinder. and, piston members, oneioiisaidmembersbieing attachedto saidrdri'll string and the other member beingattached to said"dril-1'-bit and" movable with regard to said string,variable stroke means for reciprocating the movable member, said meanscomprising passage"meansfonadmitting a pressure fluid from the.drilrstringtb'the cylindermember to one side of saidpiston, passagemeans for exhausting the fluid from the cyl'i'nder on the other side ofthe piston, .a passage through the piston, said passage having arestrictedportion, a hollow cup-shaped valve.adapted-toclose said pistonpassage to fluid flow during the upward stroke of the movable member,alcupimember afiixed to thepiston member'in': register with the openface of the cupshapedzvalve, pin means aflixedto-the cylinder memberadjacent the passage means for exhausting the fluid therefrom andadapted toforce said valve to an open position in contact with said capmember, channel means through the walls of the cup-shaped valve incommunication between the restricted portion of the piston passage andthe closed space defined within the cup-shaped valve when said valve isin contact with said cap member, whereby said cup-shaped valve ismaintained in an open position in contact with said cap member by aVenturi suction effect created by the fluid flow through said restrictedportion of the piston passage during the downward stroke of the movablemember, and is released to a closed position by a decrease of said fluidflow and of said suction efiect occurring when the motion of the movablemember is arrested by'the impact of the drill bit against the bottom ofthe borehole, a valve affixed to the movable member and adapted to seatagainst the fluid exhaust passage, spring means tending to maintain saidvalve open, yieldable means adapted to force said valve closed bycontact therewith at the end of the upward stroke of the movable member,said valve being adapted to remain closed byfluid pressure within thecylinder against the action of said spring means during the downwardmotion of said movable member, and leakage means through the walls ofthe movable member adapted to relieve said pressure, whereby said valveis maintained open by said spring means during the upward stroke of saidmovable member.

3. A hydraulic device adapted to be lowered on a drill string into aborehole for impacting a drill bit against the bottom thereof, saiddevice comprising a piston attached to said string and a cylinderadapted for reciprocation about said piston, said cylinder having thebit attached thereto, passage means for admitting a pressure fluid fromsaid string to said cylinder above said piston, passage means forexhausting the fluid from the cylinder below said piston, a passagethrough the piston, said passage having a restrict ed portion, a hollowcup-shaped valve adaped to close said piston passage to fluid flowduring the upward stroke of the cylinder, a cap member connected to thepiston member above the cupshaped valve in register with the open facethereof, yieldable pin means aflfixed to the cylinder below said pistonadapted to force said valve to an open position with its open face incontact with said cap member at the end of said upward stroke, andchannel means in fluid communication between the restricted portion ofthe piston passage and the closed space defined within the cupshapedvalve whensaid valve is in contact with said cap member,,,whereby saidcup-shaped valve is maintained in an open position in contact with saidcap member by a Venturi suction effect created by the fluid flow throughsaid restricted portion of the piston passage during the downward strokeof the cylinder, and is released to a closed position by a decrease ofsaid fluid flow and of said suction effect occurring when the motion ofthe cylinder is arrested by the impact of the drill bit against thebottom of the borehole.

4; The device of claim 3, comprising coil spring means disposed belowthe piston within the cylinder, said spring means being adapted to becompressed between the piston and the cylinder during the upward strokeof the cylinder and to expand during the downward stroke of thecylinder.

5.- The device of claim 1, having a clutch for imparting a rotary motionto the drill bit by means of the drill string, said clutch comprising afirst annular toothed member fixedly connected to the drill bit memberof the device, a second annular toothed sleeve member concentric withthe drill string member of the device and adapted for sliding motionwith regard thereto, pin and slot means connecting said sleeve and drillstring members and adapted to translate a rotational motion of the drillstring member into an axial motion of the sleeve member, whereby saidtoothed sleeve member is caused to engage the toothed member connectedto the drill bit member, spring means frictionally connecting saidsleeve and said drill bit members, and spring means engaged between saidsleeve and said drill string members and adapted to urge said sleevemember away from said first toothed member.

6. The device of claim 1, having as fluid exhaust means an axial boreextending into the drill bit, radial passages in communication betweensaid b'ore and the outside of the bit, an axial cavity in the body ofthe bit in register with said bore below said passages, a metallic plugin said cavity, and frangible means retaining said plug in said cavity,said plug being adapted to be pressed out of said cavity and intocontact with said bore to close said bore by direct pounding against thebottom of the borehole when the lower part of said bit is worn out tothe level of said plug.

'7. The device of claim 1, having radial port means in fluidcommunication between the inside and the outside of the drill stringabove said piston member, valve means adapted to close said ports, andspring means adapted to maintain said valves closed at fluid pressureswithin said drill string below a predetermined maximum.

8. A hydraulic device adapted to be lowered on a drill string into aborehole for impacting a drill bit against the bottom of the borehole,said device comprising a cylinder member and a piston member, one ofsaid members being attached to the drill string and the other memberbeing attached to the drill bit and being movable with regard to thedrill string, and variable stroke means for reciprocating the movablemember, said means comprising passage means for admitting a pressurefluid from the drill string into the cylinder member to one side of thepiston member, passage means for exhausting said fluid from the otherside of the piston member, a passage through the piston member, saidpassage having a restricted portion, a cap member rigidly connected tothe piston member above said passage and coaxially therewith, a hollowcupshaped valve member adapted to close said passage to fluid flowduring the upward stroke of the movable member, pin means carried by thecylinder member below said piston adapted to force the open face of saidhollow valve member against said cap member at the end of the upwardstroke, thereby opening said passage to fluid flow, and channel meansthrough the walls of the cupshaped valve in communication between therestricted portion of the piston passage and the closed space definedwithin the cup-shaped valve when said valve is in contact with said capmember, whereby said cup-shaped valve is maintained in an open positionin contact with said cap member by a Venturi suction effect created bythe fluid flow through said restricted portion of the piston passageduring the downward stroke of the movable member, and is released to aclosed position by a decrease of said fluid flow and of said suctioneffect occurring when the motion of the movable member is arrested bythe impact 13 of the drill bit against the bottom of the borehole.

9. A hydraulic device adapted to be lowered on a tubular string into aborehole for impacting a drill bit against the bottom thereof, saiddevice comprising a cylinder and a piston, said piston being attached tothe string and said cylinder being attached to the bit and movable withregard to thegstring, and variable stroke means for reciprocating thecylinder, said means comprising passage means for admitting a pressurefluid from the string to the cylinder above the piston, passage meansfor exhausting the fluid from the cylinder below the piston, an axialpassage through the piston, said passage having a restricted portion, acap member affixed to the piston co-axially with said passage, a movablehollow cup-shaped valve member adapted to close said piston passage tofluid flow during the upward stroke of the cylinder, said cup-shapedvalve member having an open face in register with said cap member, pinmeans aifixed to the cylinder below said piston adapted to forcethe openface of the cup-shaped valve member into a position in contact with saidcap member at the end of the upward stroke of the cylinder, therebyopening the piston passage, and channel means in 14 communicationbetween the restricted portion of the piston passage and the spacedefined by said hollow cup-shaped valve member and said cap member whensaid members are in contact with each other, whereby said cup-shapedvalve member is maintained in said position by a Venturi suction effectcreated by the fluid flow through said restricted portion of the pistonpassage during the downward stroke of the cylinder, and is released to aposition closing the piston passage upon a decrease of said fluid Howand said suction effect occurring when the motion of the cylinder isarrested by the impact of the bit against the bottom of the "borehole.

EUGEN MERTEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

